Question

The correct code for stability, of oxidation states for given cations is

I. $Pb^{2 +}>Pb^{4 +},Tl^{+} < Tl^{3 +}$ II. $Bi^{3 +} < Sb^{3 +},Sn^{2 +} < Sn^{4 +}$

III. $Pb^{2 +}>Pb^{4 +},Bi^{3 +}>Bi^{5 +}$ IV. $Tl^{3 +} < In^{3 +},Sn^{2 +}>Sn^{4 +}$

V. $Sn^{2 +} < Pb^{2 +},Sn^{4 +}>Pb^{4 +}$ VI. $Sn^{2 +} < Pb^{2 +},Sn^{4 +} < Pb^{4 +}$

• A. V and VI
• B. I, III and VI
• C. III and V
• D. II and IV

Answer 1

Answer: (C)

Due to inert effect the stability of lower oxidation state gradually increases while stability of higher oxidation state gradually decreases down the group in elements of group 13th to 15th. So correct order are

III. $Pb^{2 +}>Pb^{4 +},Bi^{3 +}>Bi^{5 +}$

IV. $Sn^{2 +} < Pb^{2 +},Sn^{4 +} < Pb^{4 +}$